Don't know why this would happen with SRM off, but the SRM system continues to operate for about 3 seconds when you shift to neutral with the clutch depressed. It is programmed to rev the engine, even when shifting to neutral, to anticipate a downshift. Try shifting to neutral at 70mph and see what it does....it'll rev the crap out of the engine.
So, it doesn't explain why it would do it with SRM off or when stopped. But the SRM will rev it even when shifting to neutral if you're at speed.
Late,
Trav
|